The transistor circuit diagram you are showing appears to be an extremely unusual circuit, especially when using capacitors in microfarads.
I think I read from Harry's homebrew that "Amplifiers oscillate" and "oscillators amplify".
To be simple, the output must be constantly on and off, not always in one state, or you will have a basic switch. I find that a large capacitor between base and collector can make things 100% worse because you will have to depend on the transistor to slow it's speed down greatly, and it wont want to do that.
Let me explain how I think it could work with a capacitor and an NPN:
1. A signal is injected into the input (-ve).
2. The output is +ve.
3. The capacitor gets charged
4. When the input signal is inverted, the output will remain +ve because the capacitor is holding the +ve charge.
now if we replaced the capacitor with a resistor, then we have action like so:
1. A signal is injected into the input (-ve).
2. The output is +ve.
3. The +ve signal is directly injected back to input through the resistor, forcing it to be +ve.
4. The output is now -ve, and the -ve signal is fed back to input through the resistor.
5. The process repeats.
The operations mentioned above are altered if a constant +ve signal is injected into the input.
I like capacitors from emitter to ground. I think they can be great signal extenders, because whatever +ve signal is applied to the input is applied to the capacitor. When the input drops, it does not drop immediately. Instead, it drops slowly, depending on the capacitor.